Spindle reciprocating mechanism for grinding machines



Oct. 3, 1939. B. A. KEARNS SPINDLE RECIPROCATING MEGHANISM FOR GRINDINGMACHINES Filed March 28, 1938 5 Sheets-Sheet l B. A. KEARNS Oct. 3,1939.

SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES 5 sheets-sneu 2Filed March 28, 1938 MJHNI m Oct. 3, 1939. l B. A. KEARNs SPINDLERECIPROCATING MECHANISM FOR GRINDING MACHINES 5 Sheets-Sheet 5 FiledMarch 28, 1938 ATTORNEY.

B( A. KEARNs oct. 3, 1939.

SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES Filed March 281938 5 Sheets-Sheet 4 ATTORNEY.

Och 3y i939., B, A, KEARNS A 2,175,157

SPINDLE RECIPROCATING MECHANISM FOR GRINDING MACHINES Filed March 28,1958 5 sheets-sheet 5 jeg ATTORNEY.

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Patented Oct. 3, 1939 UNITED lerares SPINDLE RECIPROCATING MECHANISM FORGRINDING MACHINES Bernard A. Kearns, Cincinnati, Ohio, assigrxor toCincinnati Grinders Incorporated,

Cincinnati,

Ohio, a corporation of Ohio Application March 28, 1938, Serial No.198,440

1.3 Claims.

This invention relates to grinding machines and more particularly to animproved spindle reciprocating mechanism therefor.

One of the objects of this invention .is to provide a new and improvedmechanism for axially feeding the spindle of a grinding wheel, eithermanually or automatically.

Another object of this invention is to provide a mechanism of thecharacter described which Imay be conveniently operated manually by theoperator to effect continuous reciprocation, or automatically actuatedto perform a single stroke.

A further object of this invention is to provide a mechanism which isespecially suitable for finish grinding a square shoulder on a Workpiece at the same time that the diameter is finished.

An additional object of this invention is to provide a mechanism whichis especially useful for shoulder grinding work and which is adjustableso that compensation may be made for wheel wear.

Other objects and advantages oi the present invention should be readilyapparent by reference to the following specification considered inconjunction with the accompanying drawings' illustrative of oneembodiment thereof, but it will be understood that any modifications maybe made in the specc structural details within the scope of the appendedclaims without departing from or exceeding the spirit of the invention.

Referring to the drawings in which like reference numerals indicate likeor similar part's:

F.' gure 1 isa side elevation of a grinding Wheel head unit showing theapplication of this invention thereto.

Figure 2 is a detail section on the line 2 2 of Figure 1 showing thespindle actuating piston.

Figure 3 is a detail section on the line -t of Figure 2.

Figure 4 is a vertical section through the grinding wheel spindle asviewed on the line il-4 of Figure 1.l

Figure 5 is an enlarged detail of a ratchet stop mechanism.

Figure 6 is an enlarged vertical section through the actuating mechanismfor the spindle as viewed on the line 6-6 of Figure 4.

Figure 7 is a detail sec-tion on the lirici-'H of Figure 6.

Figure 8 is a section on the line 8 8 of Figure 6.

Fgure 9 is a detail section on the line S- of Figure 5.

Figure 10 is a detail section on the' line lil-I0 of Figure 6.

Figure 11 is a detail section on the line Il-II of Figure 6.

Figure 12 is a detail section on the line 12-12 of Figure 8.

Figure 13 is a diagrammatic view showing the relationship between agrinding wheel and a Work piece.

Figure 14 is an lil-iii of Figure 6.

One of the items which adds to the cost of manufacturing multiplediameter work pieces is the operation of finishing the internal cornersformed by two intersecting surfaces. A common example of this is theinternal corner formed by a shoulder at one end of a cylindricalsurface. If the cylindrical surface is to serve as a bearing member, andthe shoulder asa lateral guide, it will be apparent that a part mountedon the cylindrical surface must have unhindered utilization of thatsurface in order that the shoulder may serve -as a guide. It istherefore essential that no superfluous material be left in the cornersby the manufacturing processes. Heretofore, an extra machining operationwas usually necessary in order to remove this material.

This invention is directed to a mechanism for so manipulating thegrinding wheel that it will not only simultaneously finish grind the twointersecting surfaces but will also produce a square corner between thetwo surfaces in such a manner that subsequent finishing operations areunnecessary.

Briefly, this is accomplished by supporting a grinding wheel indicatedby the reference numeral ii! in the diagrammatic sketch, Figure 13, foroscillation about an axis li which is arranged at a slight angle withrespect to the axis of rotation i2 of the work piece I3. If the axis ofrotation li is arranged below the laxis of rotation Il! of the grindingwheel, as shown in Figure 1,

enlarged section on the line it vwill be apparent that as the grindingwheel support l5 moves about the axis il, that the grinding Wheel il)will move toward and from the work piece I3. On account of the angularrelationship of the axes i l and I2, the grinding wheel will not movetoward the workalong a path perpendicular to the axis indicated by thereference numeral I6 in Figure 13 whichis perpendicular to the axis lland therefore slightly. inclined with respect to the axis I 2. Thismeans that the grinding wheel can be trued to provide a first grindingsurface l1, and a second grinding surface I8, having an included angleof intersection I9 which is equal l2 but along a path y to the angle ofintersection 28 of the cylindrical surface 2i of the work and the facel22.

In addition, the grinding wheel is provided with a movement parallel toits axis of rotation and in a direction indicated by the arrow 23V inFigure 13. If the movement along the path I8 and the one along the path23 are executed simultaneously there will be a resultant movement alongthe path 24. It will be noted that if the grinding wheel can follow thepath -24 in moving toward the work piece, that the corner 25 of thegrinding wheel will move directly toward the internal corner 26 of thework piece, and in so doing will simultaneously grind both thecylindrical surface 2| and the face 22. The mechanism for reciprocatingthe grinding wheel either manually or automatically, whereby this andkindred results may be obtained, will now be described, the manualcontrol mechanism being described iirst.

In Figure 1 of the drawings, the reference numeral 21 indicatesgenerally a grinding wheel support unit, which may be mounted on a fixedsupport, such as 28, with the axis of the grinding wheel parallel to theaxis of the work, a8 when grinding cylindrical surfaces having shouldersat each end; or inclined to the axis of the work as suggested inconnection with Figure 13.

The grinding wheel I8 is supported on the end of a spindle 28, Figure 4,which is antifrictionally journaled at spaced points 38 and 3l in thehousing l5. The end of the spindle opposite to the grinding wheel isprovided with a driving pulley 32 which, as shown in Figure 1, may beconnected by a plurality of belts 33 to a driving pulley 34 secured tothe end of the armature shaft of the motor 35. Thus the spindle isadapted to be power rotated by means self-contained in the housing l5and movable therewith.

The spindle 29 has an intermediate collar 88, which is antifrictionallyconnected to a ring 81, the ring being pivotally connected atdiametrically opposite points to a lever 38 which is pivotally supportedat 39 in the housing I5 and operatively connected at the outer end 48 toa reciprocating mechanism. It should now be apparent that as the end 48of the lever 38 is moved in the plane of Figure 4, that the grindingwheel spindle will be axially moved.

The mechanism for reciprocating the spindle is more particularly shownin Figure 6, and is entirely contained in a housing 4l which is adaptedto be mounted and secured over the top of an opening 42 in the supportI5, and automatically operatively interconnected with the end 48 of thelever 38 upon assembly.

There is a vertical sleeve 43 which is antifrictionally supported at 44and 45 in the housing 4l. The end of this sleeve, as shown in Figure 4,is provided with a guideway 46 in which slides a pin carrying slide 41.,A pin 48 carried by this slide ts in a block 48, as shown in Figure 11,the block fitting in across slot 58 formed in a plunger 5I. This plungeris surrounded by a sleeve 52 which has a portion cut away toformshoulders 53, and means are provided whereby the plunger 5l iscontinuously urged in the direction of arrow 54, and the sleeve 52 iscontinuously urged in the direction of arrow 55 whereby any lost motionbetween the plunger 5I and the sleeve 52 is climi nated.

The end 40 of lever 38 ts between the end of plunger 5I, and the end ofa second plunger 56 which is urged in one direction by a spring 51interposed between the end of the plunger and a plug 58 fixed in the endof the sleeve 52. It

is this spring which continuously urges the parts shown in Figure 11 inopposite directions. It will beapparent that if` the pin 48 is locatedeccent'rlcally to the axis of rotation of the sleeve 43, that when thesleeve is rotated the pin will cause movement of lever 38 by means ofthe mechanical connections j ust described.

No positive stops are providedfor limiting the,

movement of the spindle, the length of movement being controlled byoscillating the pin 48, 90 to "each side of a center position. Thereforethe axis of eccentricity of the pin is made to normally lie in a planeperpendicular to the axis of rotation of the spindle in order todetermine the center position. The movement of the spindle in eachdirection from this center position will then depend upon the length ofthe effective radius of eccentricity. Therefore, means are provided forcentralizing the pin, and thereby the spindle in this center position.This aids in work set-up.because a work piece having an annular grooveand opposing shoulders to be ground, may be positioned with the centerof an annular groove in the plane of this center position.

By adjusting the eccentricity of the pin to make the radius equal toone-half oi the desired width of the groovethe grinding wheel may bemoved into the center of the groove and then oscillated to grind theshoulders.

This centralizing mechanism comprises an elongated sleeve 58, Figures 6and 14, upon the periphery of which are cut rack teeth 68 whichinter-mesh with gear teeth 6| cut in the periphery of the sleeve 43. Thesleeve 59 has cap members 62 mounted in each end and interconnected by aspring 63 which passes through the center of the sleeve. The capmembers' are sufllciently large in diameter to overlap the sleeve andlengage a part of the housing 4l. The sleeve is made of the properlength so-that when both cap members are in engagement with the housingthere is The fixed housing 4I has an upstanding bracket 81 attached toone side, as by screws .88, and the upper end of this bracket has anelongated tubular portion 68 which forms a vertical bearing fora crankhousing 10. This crank housing 'carries two pins 1l and 12 which, asshown in Figure 8, depend into engagement with opposite sides of theroller 86 whereby upon rotation of the crank, the roller 88 is picked upand moved to rotate the sleeve (i3. The upper end of the housing 18 hasa boss 13, as shown in Figure 7, through which is formed a bore 14 forreceiving an operating lever 15. The boss 13 is split on one side andclamping bolts 18 serve to draw the two parts together and clamp thelever 15 in proper longitudinal position.

The lever 15 consists of a tube, on one end of which, as shown in Figure6, is mounted a second telescoping tube 11. A split collar 18 serves toclamp the parts together and at the same time permit telescopingadjustment to carry the length of the operating lever. It will be notedthat the operating lever 15 extends toward the operator's 2,175,057position on the side of the' work opposite to the grinding .wheel I0, asmore particularly shown in Figure 1. When the operator oscillates thelever 15, he will rotate the crank housing 10 and thereby, through thepin and roller connection, rotate the housing 65 and the sleeve 43integrally connected therewith, whereby the pin 48 eccentricalQ lycarried on the lower end of the sleeve 43 will move in an arc about theaxis of rotation of the sleeve 43 and cause axial movement of thegrinding wheel spindle in either direction from its normal centralposition.

lWhen the grinding wheel is used to grind both the diameter and twoshoulders at opposite ends of an annular groove in a work piece, it willbe;

apparent that it is necessary to true the sides of the wheel as well asthe peripheral surface in order to maintain square corners on the workpiece. It will be Iobvious that as the sides of the 'wheel are 'truedaway, the width of the wheel grows smaller whereby a greater strokebecomes necessary in order to move the sides of the wheel into contactwith the shoulders and grind the width of the groove to the same size.Since the stroke of the grinding wheel is dependent upon theeccentricity of the pin 48, it will be obvious that the stroke can onlybe changed by varying the eccentricity of this pin. Means have thereforebeen provided whereby the eccentricity of this pin may be varied, andthis mechanism is so contrived that it may be actuated from theoperators position by means of a plunger 19 located in the end of thelever 15.

It is to be understood that the eccentricity of the pin will be aminimum when the grinding wheel is new and that as the grinding wheelwears away, the plunger is actuated to increase the eccentricity of thepin. This plunger is frictionally held in the end of a. tube 80 and maybe axially adjusted -relative thereto whenever the outer telescopingsleeve 11 is adjusted relative to the lever 15 so that the plunger 19always projects beyond the end of the tube 1. The plunger 19 comprises atube 8| which is split on the inner end and has a taper ended draw bar82 which is threaded in the end of the head 83 so that as the draw baris pulled axially by rotating the head 83, the end of the tube 8U willbe expanded within the tube 90 and frictionally locked.

The tube 80 carries a'collar 84, and a spring d5 n is mounted betweenthis collar and a fixed sleeve 88 carried within the member 15. The endof the sleeve 80 has a tubular rack member 81 attached to the endthereof, as shown in Figure '1, in intermeshing relation with a pinion88. The pinion @8 is keyed to the upper end of a shaft 89, as shown inFigure 6, and the lower end of this shaft is reduced in diameter andprovided with pinion teeth 90 which intermesh with a gear segment 9|.

Referring to Figure 8, the gear segment 9| is supported for freerotation on the end of an upstanding pin 92. The segment 9| carries aradial arm 99 in the end of which a pawl 94 is pivotally mounted. Aspring 95 normally urges this pawl into engagement with teeth 96 of aring gear 91. The housing 61 has an L-shaped portion 98 surrounding thepawl and providing a shoulder 99 which is adapted to engage the heel ofthe pawl so that when the segment 9| is moved clockwise to its extremeposition, the pawl 94 will be out of engagement with the gear teeth.Upon axial movement of the plunger 19 toward the right, as viewed in`Figure 6, the pinion 88 will be rotated and thereby through the pinion90 will cause movement of the gear segment 9| in a counterclockwisedirection whereby the heel of the pawl will move away from 4the shoulder99 and the spring 95 will cause engagement of the pawl with the gearteeth thereby rotating the gear 91.

The gear 91v which is supported for free rotation on the pin carried bythe housing 65. The segment |00 has a radial arm |02 which ts into aslot |03 of a slide |04. The slide |04 carries twin pawls |05 and |06which are normally urged into engagement by a leaf spring |01 with teethon the periphery of a ratchet wheel |08. The ratchet wheel |08, as shownin Figure 14, is pinned to the end of a shaft |09 which carries a worm||0. 'Ihis worm meshesgwith a. worm wheel keyed to the upper end ofshaft I2. The shaft H2, as shown in Figure 6, passes directly throughthe center of the sleeve 43 and is provided on the lower end with pinionteeth ||3, as more particularly shown in Figure 10. These pinion teethmesh with a short rack bar I4 which is fastened by bolts to the slide41.

'A second rack bar directly under the rack'bar |4 and continuously urgedin one direction by a spring pressed plunger ||1 so as to take out lostmotion between the pinion ||3 and the slide 41. In Figure 10, the axisof rotation of the sleeve 43 is indicated by the reference numeral ||8,and it will be noted that the rack bar moves parallel to a radial lineH9 passing through the center |18 and the center |20 of the pin 48.Since the pinion l I3 is xed in space, it will be apparent that upon itsrotation that the slide 41 will be moved in a direction to vary theeffective eccentric radius of the pin 4E.

The amount of change that can be effected in the eccentricity of the pinfor a given stroke of the plunger 19 may be made very small and isdetermined by the setting of two set screws |21 and |22, shown in Figure8. These set screws urges the lever |02 in a counterclockwise direcltion against the set screw |2| thereby returning the ratchet pawls |05and |06 into position for the next' stroke. As the slide |04 returnsthese pawls to the position shown in Figure 12, the heels |24 of thesepawls.engage a plate |25 thereby rotating the pawls in a clockwisedirection a suicient amount to disengage them from the ratchet wheel.This makes it possible to reset the mechanism when a new grinding wheelis placed in the machine, because the shaft |09 which carries theratchet wheel |08 projects beyond its housing, as'shown in Figure 14,and is provided with a square end |26 to which-may be applied a suitablecrank for rotating the shaft |09 in a clockwise direction to effectretraction of the pin 48 toward the center ||8.

If so desired, a pair of positive stops may be provided for limiting theoscillating movement of the crank housing by providing a pair of stopscrews |21 and |28 which are threaded into the housing 10 and in suchposition that as the housing rotates about the center of the bearing 69,the ends of the screws will alternately contact on opposite sides of theenlarged diameter |29 of pin 92. Conventional power operable means maybe utilized to eiect' the movement of the grinding wheel toward and fromthe work meshes with a gear segment |00' Hs is mounted in the slide |33having a reduction worm and worm gear and the rate of this movement maybe controlled by a suitably formed cam |30 which, as shown `in Figure 1,is supported on a rotatable shaft |3| in adjacent relation to the underside of the sup-v port I whereby the support may be provided with aroller |32 for contacting the periphery of the cam. The cam may beactuated by a motor such a rate that one revolution of the cam will theend ofthe sleeve.

effect a complete cycle of the grinding wheel toward and from the work.

It may be desirable to effect automatic lateral movement of the grindingwheel in timed .relation to the automatic ineeding movement and e ifthis is desired a second control cam |31 may be applied to the shaft |3|and provided -with a spring urged follower |38 which has a leverconnection |39 to a control valve |40.'

' For purposes of lillustrating one manner of obtaining automaticcontrol, mechanism has been disclosed herein for effecting automaticlateral movement of the `grinding wheel for work that falls under theclass illustrated in Figure 13. In this ca se, it is only necessary tomove the wheel laterallyin one direction until the shoulder has beenground to the desired dimension after which the wheel is retracted and anew work piece substituted. g l v This movement may be effected by apiston |4| which, as shown in Figure 2, may be, slidably mounted in acylinder |42 attached to the end of the housing 4| and in axialalignment with the sleeve 59. In order not to interfere with the spr-ingcentering means*A for the sleeve, the cap4 member 62, as shown in Figure3, may be cut away to permit the fingers |43 integral with the end ofthe piston |4| to pass through and engage Thus, upon admission of fluidpressure to the end of cylinder |42, the sleeve v59 will be moved andthereby through the rack and pinion connection with' the sleeve 43, thepin 48 may be moved in a direction to shift the grinding Wheel in adirection towards the shoulder 22 of the work.

The end of the cylinder |42 is connectedI by a channel |44, as moreparticularly shown in Figure 1, to a port of the control valve |46 whichcontains the valve plunger |40. This valve may have a pressure port |41which ls supplied from a suitable source' of pressure, such as a pump|48, having an intake |49 through which fluid is withdrawn from areservoir |50. The pump may be provided with a relief valve |5|. Theplunger |40 has two annular grooves |52 and |53 whereby when the plunger|40 is shifted to the left, the port |41 will be connected to port |45and pressure fluid will flow to the end of cylinder |42. When theplunger |40 is shifted to its right hand position, the port |45 will beconnected to` an exhaust port |54 which is connected by a return channel|55 to reservoir |50. l

Thus, the admission of uid pressure to the cylinder |42 may beautomatically controlled from the cam |31 and the rate of flow may begoverned in accordance with the amount that the pressure port |41A isopened.

In order to limit the movement `of the sleeve 59, the opposite end ofthe housing 4| 4may be provided with a cup shaped member |56 inwhich'ticularlyin Figure 5.

is threaded an adjustable stop screw I |51 axially aligned with thescrew |58 threaded in the end of the cap member 62 and holding one endof lthe spring 63. By adjusting the stop screw |51,

the movement of the sleeve 59 may be adjusted to thereby determine thethrow ofthe spindle actuating pin 48.

In order to prevent interference from -the mechanism shown in the upperpart of Figure 6 with power rotation of the sleeve 43, the pin 12, shownin Figure 8, may be withdrawn,whereby lupon rotation of the housingwhich is integrally connected with-,the sleeve 43, there will be nofeed-back motion transmitted to the crank arm 10, and this may be,locked in position by a set screw |59 which is threaded in the housingand engageable with part of the fixed bearing 69. Additionally, thestopscrew |28 may be backed away or removed to prevent interfering with themotion.

As previously mentioned, the grinding Wheel I0, shown in Figure 13, willhave the face I8 as well as the face I1 periodically trued, which meansthat for the same starting position of the grinding wheel, the distancebetween the face i3 of the wheel and the face 22 of the work willgradually increase thereby normally requiring a. greater stroke in orderto effect the desired contact between these surfaces so that the workmay be ground. movement down to a minimum, means have been provided forlimiting the return stroke to a maximum predetermined amount. Themechanism for accomplishing this is shown more parsleeve 52 is providedwith a toothed block |60 and over this block and pivotally mounted on apin |6| are pawls |62. y

The teeth onnthe block |60 are spaced a sufiicient distance apart topermit a maximum reciprocating movement of a desired amount, such as 115of an inch or 3% of an inch, after which one of the pawls will engage atooth so as to reduce the return movement. In other words, the st'pscrew |51, shown in Figure 2,.limits the movement of the sleeve 59 inone direction, and although the spring 63 tends to return the parts inthe other direction, the pawls |62 limit this return. Thus the stroke ofthe piston |49 is gradually reduced so that the starting position Inorder to keep this waste The end of the movable t:

return to the same position'each time for truing v and therefore meanshave been provided for releasing the pawls |62 so that the spring 63 cancentralize the parts for truing. In addition, it is desirable that noinadvertent movement of the cutter spindle take place during truing andtherefore means have also been provided for locking the sleeve 52. Thismechanism comprises a lever arm |63 integral with the pawls and engaginga shoulder |64 on a bar |65. This bar has a threaded engagement with theend of` a vertical plunger |66. The lever arms |63 are continuouslyurged in a counter-clockwise direction by a spring pressed plunger |61which also serves to hold the pawls in engagement with the teeth on themember |60. 'I'he leverarm |63 is also provided with an arm |68 which',upon clockwise rotation, will engage the sleeve 52 and lock the same.

For the purpose of merely releasing the pawls from' engagement with theteeth on member |60, the plunger |66 is simply pulled up the desireddistance, and when the pawls have become disengaged from the teeth, thespring 63, shown in Figure 14, will centralize the actuating pin. If itis desired to lock the parts for any period ol time, the plunger |66 isrotated, and since thc member |65 is held against rotation by two guidescrews |69 and |10, as shown in Figure 9, the member |65 will bepermanently held in an upward position, which will be limited by theclamp arm |68 engaging the sleeve 52. As shown in Figure 9, the member I65 will be permanently held in an upward position which will be limitedby the clamp arm 68 engaging the sleeve 52.

As shown in Figure 9, springs lll may be provided for urging the returnof the member |65 when it is merely lifted. In order to limit the axialmovement of member |66, it is provided with a groove |12 into which isthreaded the end of a limiting screw |13, there being sufcient lostmotion between the end of the screw and the groove to permit a limitedaxial movement of the plunger.

There has thus been provided an improved mechanism for the purposesdescribed whereby the spindle of a grinding machine may be manuallyreciprocated during power infeeding thereof toward a work piece, andthat additional means have been provided whereby the spindle may bemoved by power in synchronous relation to an infeed cycle, and thatimproved means have been provided to make the necessary adjustments andcompensations for wear and truing of the grinding wheel.

What is claimed is: I

l. In a grinding machine having a support, a spindle rotatably mountedon said support, and a grinding wheel attached to said spindle, .thecombination of means for eiecting axial reciprocation of said spindleduring rotation thereof, including a rotatable member, a shifter carriedthereby disposed eccentric to the axis of rotation of said member, meansoperatively connecting the shifter with said spindle, whereby uponrotation of said member, said spindle will be oscillated, and means tovary the effective eccentricity of the shifter with respect to the axisofI rotation of the member, whereby the axial movement of said'spindlefor a given angle of rotation of said member is varied,

2. In a grinding machine having a xed support,V an oscillatable supportmounted on saidV xed support: a spindle journaled in saidoscillatablesupport and. having a grinding wheel attached thereto, the combinationof means carried by said oscillatable support for reciprocating thegrinding wheel spindle during rotation thereof and during movementtoward a work piece, including an oscillatable member, power means foreiecting successive oscillations of said member during the grindingoperation, la pin located eccentrically to the axis of oscillation,means operatively connecting the pin for axial movement of said spindle,and axially arranged means within said oscillatable member and movablerelative thereto `for adjusting'the eccentricity of said pin to therebyvary the throw thereof fora given angular movement of said member.

3. In a machine tool having a xed support, an oscillatable supportmounted thereon, and a grinding wheel spindle journaled in saidoscillatable support and having a grinding wheel attached thereto formovement toward and from a work piece vupon movement ofsaidioscillatable support, the combination of a housing carried by saidoscillatable support, a manually operable control lever pivotallymounted on said housing for oscillationl by the operator, motiontransmitting connections carried by said housing for transmitting themotion of said lever to said spindle for effecting a limited axialmovement thereof, said means including an adjustable eccentric, andmeans carried by said control lever and movable axially thereof forincreasing the effective throw of said eccentric connection.

4. ln a grinding machine having a grindingwhe-el, a spindle therefor,and a support for mov:- ing the grinding wheel toward and from a workApiece, the combination of means carried by said support for effectinglateral movement of the grinding wheel while in engagement with a workpiece to grind shoulders thereon, including a housing carried by saidsupport, a rotatable sleeve in said housing, motion transmittingconnections .from said sleeve to said spindle, means for oscillatng saidsleeve, including a roller eccentrically connected to the upper end ofsaid sleeve, a crank arm supported for rotation about an axis parallelto the axis of oscillation of said sleeve and having a pair of dependingmembers engaging opposite sides oi said roller, and manually operablemeans for oscillating said crank arm..

'5. In a grinding machine having a grinding wheel, a support, and aspindle for supporting said wheel for rotation relative to said support,the combination of means for reciprocating said spindle while thegrinding wheel is in engagement with said work, including a reciprocableplunger` operatively connected to said spindle, a crank arm engagingsaid plunger, manually operable means for oscillating said crank arm,and means normally maintaining said crank arm in a plane perpendicularto the axis of said plunger, including a tubular member, caps engagingopposite ends of said tubular member and fixed parts of the housing, andresilient means passing through said tubular member and connected atvopposite ends of said cap members.

6. In a mechanism for eiecting oscillation of a grinding wheel, ahousing for supporting said grinding wheel spindle, a plungerreciprocably mounted in said housing for movement parallel to the axisof said spindle, a pair of parallel rotatable members mounted in saidhousing, a crank connection for transmitting rotary motion from one ofsaid members to the other, one of said members carrying a crank pinengaging said plunger, a slide supporting said pin, means to adjust saidside to vary the eccentricity o1' said pin,

' including shafts extending axially through each able by the shaft insaid second sleeve for effecting a predetermined amount of rotation ofsaid gear, and a second ratchet means operable by said gear forimparting rotation to the shaft mounted in the first sleeve,

8. In a mechanism for effecting axial moven ment of a grinding wheelspindle and attached grinding wheel supported for rotation and radialmovement toward a work piece, the combination of a rotatable sleeve, aneccentric pin carried by said sleeve and operatively connected to saidspindle, fluid operable means connected to said sleeve for effecting onedirection of rotation thereof, and thereby one direction of axialmovement of said spindle, manually operable means inlcuding a shaftpassing through said sleeve for adjusting the-eccentricity of said pin,and resiliently operable means for returning said sleeve when fluidpressure lis removed from said -uid operable means.

9. In a mechanism for effecting axial movement of a grinding wheelspindle and attached grinding wheel supported for rotation and radialmovement toward a work piece, the combination of a rotatable sleeve, aneccentric pin carried by said sleeve and operatively connected to saidspindle, fluid operable means connected to said sleeve for effecting onedirection of rotation thereof, and thereby one direction of axialmovement of said spindle, manually operable means including a shaftpassing through said sleeve for adjusting the eccentric'ity of said pin,resiliently operable means for returning said sleeve when fluid pressureis removed from said fluid operable means,

and means for limiting the return movement effected by said resilientlyoperable means when the advancing movement exceeds a predeter minedamount.

10. In a mechanism for effecting axial movement of a grinding wheelspindle and attached grinding wheel supported for rotation and radialmovement toward a work piece, the combination of a rotatable sleeve, aneccentric pin carried by said sleeve and operatively connected to saidspindle, fluid operable means connected to'said sleeve for effecting onedirection of rotation thereof, and thereby one direction of axialmovement of said spindle, manually operable means including a shaftpassing through said sleeve for adjusting the eccentricity of said pin,resiliently operable means for returning said sleeve when fluid pressureis removed from said iluid operable amount.

means, and automatically operable `means for shortening the returnmovement when the advancing movement exceeds a predetermined 1l. Amechanism for reciprocating the grind- Aing wheel spindle of a grindingmachine, including a rotatable member carrying an adjustable crank pin,motion transmitting connections connecting said pin for movement of thespindle, fluid operable means for rotating said member in one direction,resiliently operable means for rotating the member in an oppositedirection, means carried by the member for increasing the eccentricityof said pin, ratchet means for decreasing the return movement of saidspindle when the advancing movement exceeds a predetermined amountwhereby the length of movement of said spindle will remain withinprescribed limits, and manually operable means for releasing saidratchet means to permit full return u movement of said spindle.

12. A mechanism for reciprocatingthe grinding wheel Aspindle of agrinding machine, including a rotatable member carrying an adjustablecrank pin, motion transmitting connections connecting said pin formovement of the spindle, fluid operable means for rotating said memberin one direction, resiliently operable means for rotating the member inan opposite direction, means carried by the member for increasing theeccentricity of said pin, ratchet means for decreasing the returnmovement of said spindle when the advancing movement exceeds apredetermined amount, manually operable means for releasing said ratchetmeans to permit full return movement of said spindle, and clamping meansoperable by said manually operable means for holding the spindle in a,fixed position during truing operations on the grinding wheel.

13. A mechanism for effecting synchronized lateral and axial movement ofa grinding wheel spindle of a grinding machine, comprising anoscillatable support for supporting the grinding wheel spindle, poweroperable means for moving said support in one direction to feed thegrinding' wheel toward the work, including a. power driven shaft, a camcarried by said shaft and peripherally engaging said support, meanscarried by the support for moving the spindle laxially, including afluid operable member, mo-

tion transmitting. connections from said member to said spindle,additional means for returning said member, a source of fluid pressure,a control valve variably positionable `for determining the rate of ilowfrom said source to said member, and a cam driven by said shaft forcontrolling the extent of variable positioning of said valve and therebythe rate of axial movement of saidv spindle.

" BERNARD A. KEARNS.

